Material mixing apparatus

ABSTRACT

Apparatus for mixing materials having no moving parts in which a plurality of elements are fitted into a conduit. The elements, which need not be permanently fastened, are self-nesting and axially overlapping. Each axially overlapping region provides a mixing matrix introducing complex velocity vectors onto the materials to be mixed. A drift space subsequent to the matrix enhances the mixing operation. The conduit and elements can be advantageously combined with a distribution head, preferably coaxial.

Unite States Patent 1 King [451 Dec. 2, 1975 MATERIAL MIXING APPARATUS I75] inventor: Leonard Tony King, Long Beach,

Calif.

[73] Assignee: Komax Systems, Inc., Carson, Calif.

[22] Filed: Dec. 27, 1973 [211 App]. No.: 428,865

[52] US. Cl. 259/4; 138/42; 239/432; 239/488 [51] Int. Cl? ..B01F 5/00;B01F 15/02 {58] Field of Search 259/4, DIG. 30; 138/42, 138/43; 239/488, 432; 261/78 A, D16. 16; 48/180 B [56] References Cited UNITED STATES PATENTS 1,874,002 8/1932 Fantz 239/432 X 3,051,453 8/1962 Sluijters 259/4 Chisholm 259/4 Grout 259/4 Primary ExaminerHarvey C. Hornsby Assistant Examiner-Alan Cantor Attorney, Agent, or FirmLimbach, Limbach & Sutton [57] ABSTRACT Apparatus for mixing materials having no moving parts in which a plurality of elements are fitted into a conduit. The elements, which need not be permanently fastened, are self-nesting and axially overlappingi Each axially overlapping region provides a mixing matrix introducing complex velocity vectors onto the materials to be mixed. A drift space subsequent to the matrix enhances the mixing operation. The conduit and elements can be advantageously combined with a distribution head, preferably coaxial.

10 Claims, 16 Drawing Figures US. Patent Dec 2, 1975 Sheet 1 of 3 3,923,288

g, aten Dec.

Shee 2 of 3 US. Patent Dec. 2, 1975 Sheet 3 f3 3,923,288

MATERIAL MIXING APPARATUS BACKGROUND OF THE INVENTION This invention relates to material mixing apparatus and particularly to stationary material mixing apparatus and to such apparatus in combination with a material distribution head for applying material to the stationary mixing apparatus. Such stationary material mixing apparatus of different construction also have been known in the prior art variously as static mixers and interfacial surface generators.

Several varieties of prior art mixing apparatus are known and disclosed in the following U.S. Pat. Nos. 3,051,452; 3,051,453; 3,182,965; 3,195,865; 3,206,170; 3,239,197; 3,286,992; 3,328,003; 3,358,749; 3,394,924; 3,404,869; 3,406,947; 3,583,678; 3,635,444; 3,643,927; 3,652,061;

3,664,638; 3,704,006; 3,733,057; and 3,751,009. Also of interest in French Pat. No. 735,033 (1932). All of the above patents are herewith incorporated by reference.

The prior art approaches typically involve expensive machining, molding, casting or other fabrication of the component mixer elements coupled with some type of permanent attachment between elements and a conduit and/or between elements within a conduit. The resulting cost and difficulty of manufacture results in a relatively expensive end product. Moreover, many of the prior art mixers provide less than complete mixing particularly with respect to material flowing along the walls of the conduit. This so-called wall-smearing is related to the parabolic velocity profile of a fluid having laminar flow in a pipe: the fluid velocity is small or zero along the wall surfaces.

SUMMARY OF THE INVENTION In accordance with the teachings of the present invention a stationary material mixing apparatus is provided comprising a plurality of self-nesting, abutting and axially overlapping elements fitted into a conduit. The elements can be inexpensively fabricated by punch pressing from flat sheets and their configuration permits assembly of the apparatus simply by stuffing the elements into a conduit. The elements tend to selfalign, abut and nest with adjacent elements and to provide a close fit to the conduit walls when a slight spring is provided in the elements. No permanent connection between elements or between elements and the conduit wall is required. Thus, the conduit can be a flexible tube if required for a given application.

When combined with a material distribution head, particularly one with a coaxial feed, the mixing apparatus can be disposable to avoid any necessity to clean the apparatus after use with reactive materials.

Each region of axial overlap between elements provides a mixing matrix introducing complex velocity vectors onto the materials. A flat axially aligned portion of each element provides a drift space subsequent to each mixing matrix for the materials to recombine prior to encountering the next matrix. The invention has been found to reduce or eliminate wall-smearing effects even when the elements are not closely fitted to the conduit walls.

The inventive apparatus is useful for mixing virtually any materials including liquids, solids, gases, foams,

etc.

2 Further advantages of the invention will be noted in the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cut-away perspective view of the stationary material mixing apparatus according to the present invention.

FIG. 2 is a perspective view of an arbitrarily designated left-hand element forming a portion of the ap- 0 paratus.

FIG. 3 is a perspective view of an arbitrarily designated right-hand" element forming a portion of the apparatus.

FIG. 4 is cut-away plan view of the apparatus of FIG. 1.

FIG. 5 is a side elevational view of the left-hand element of FIG. 2.

FIG. 6 is a plan view of the left-hand element of FIG.

FIG. 7 is a sectional view along'lines 7-7 of FIG. 5.

FIG. 8 is a side elevational view of the right-hand element of FIG. 3.

FIG. 9 is a plan view of the right-hand element of FIG. 3.

FIG. 10 is a sectional view along lines 1010 of FIG. 8.

FIG. 11 is a sectional view along lines 1111 of FIG. 4.

FIG. 12 is a sectional view along lines 1212 of FIG. 11.

FIG. 13 is a schematic cut-away view of a T-type distribution head for providing material to the stationary material mixing apparatus of this invention.

FIG. 14 is a perspective view of a portion of the distribution head of FIG. 13, showing the arrangement of the material prior to reaching the mixing apparatus.

FIG. 15 is a schematic cut-away view of a coaxial type distribution head for providing material to the stationary material mixing apparatus of this invention.

FIG. 16 is a perspective view of a portion of the distribution head of FIG. 15, showing the arrangement of the material prior to reaching the mixing apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. 1 12 wherein the stationary material mixing apparatus is shown along with its component elements. The apparatus includes a conduit 2 having an internal chamber 4 in which a plurality of elements 6 and 8 are fitted. Chamber 4 opens at the two ends of the conduit 2. A longitudinal axis passes through the length of the chamber 4.

In view of the generally cylindrical configuration of the chamber 4, the cylindrical coordinate system will be used throughout this specification and claims. As is well known, in the cylindrical coordinate system, a point is defined by l, r and 6 where l is the longitudinal coordinate, r the radical coordinate with reference to the longitudinal axis, and 6 the angular coordinate in a plane normal to the longitudinal axis.

Although the present invention is shown and described with reference to a right circular cylindrical chamber 4, it is to be understood that the invention is applicable to other configurations including chambers having a rectangular cross section. Moreover, the longitudinal axis of the chamber need not be a straight line, but may be curved due to the nature of the elements 6 and 8 as will become more apparent hereinafter.

Element 6, shown in greater detail in FIGS. 2 and 5 7, is arbitrarily designated a left-hand element and is a mirror image of element 8, shown in greater detail in FIGS. 3 and 8 10, and arbitrarily designated a righthand element.

Element 6 includes a central flat portion 10 the plane of which is intended to be generally aligned with the longitudinal axis of the chamber 4. First and second ears 12 and 14, rounded or otherwise configured at their outside peripheries for a general fit to the wall of chamber 4, are bent upward and downward from the flat portion 10. A second pair of cars 16 and 18 at the opposite side of flat portion 10, are bent downward and upward, respectively. The outside peripheral edges of ears 16 and 18 are also rounded or otherwise configured for a general fit to the wall of chamber 4.

Elements 6 and 8 may be formedfrom a single flat sheet by a punch press, for example. However, the invention is not limited to any particular manner of fabrication, nor is the invention limited to providing elements 6 and 8 as a unitary piece. For example, elements 6 and 8 could each be a plurality of pieces brazed, soldered, welded or otherwise fastened together. It will be apparent, however, that the configuration of elements 6 and 8 makes possible their manufacture out of single sheets extremely inexpensively.

Element 8 is a mirror image of element 6 and in a similar manner includes a central flat portion 20, a first pair of ears 22 and 24 and a second pair of ears 26 and 28.

The angle A between ears 12 14, 16 18, 22 24 and 26 28, best seen in FIGS. 5 and 8, is preferably in the range of about 30 to l20 with an angle of 90 being shown as one example. Obviously the extremes of 0 and 180 provide ultimate limits.

Elements 6 and 8 are alternated through chamber 4, the total number of elements used depending on the materials being mixed and the degree of mixing desired. Each consecutive element (6,8) has its flat central portion (10,20) generally perpendicular to the next element.

Reference particularly to FIGS. 1, 4, 11 and 12 shows the manner in which elements 6 and 8 readily abut and self-nest with respect to each other and with respect to the chamber 4 wall. The ears 22 and 24 of element 8 mesh or axially overlap with ears 16 and 18 of element 6 so that the ear tips are adjacent thechamber 4 wall and the central flat portion of the next element. In like manner ears 12 and 14 of element 6 mesh or axially overlap with ears 26 and 28 of element 8. The ears (12, 14, 16, 18, 22, 24, 26, 28) are preferably dimensioned to spring against the chamber 4 wall so that a good fit is made to the chamber 4 wall without any need for brazing, gluing or otherwise permanently fixing each element 6 and 8 to the chamber 4 wall. It will be apparent from the configuration of elements 6 and 8 that the elements may be stuffed into chamber 4 and that they will tend to align themselves in the desired orientation, each element self-nesting or stacking with the next element and self-locking with respect to axial rotation.

Further, it will be noted that the self-nesting or stacking feature of the elements results in a reduction of the length/diameter (L/D) ratio of the elements. For example, consider the following exemplary dimensions and L/D ratios:

Total Element Net Element Nominal Angle (k) Length Length Diameter [JD Thus, an effective L/D of less than 1.0 is possible for certain ear angles (7t).

Referring to FIG. 2, with respect to materials moving longitudinally in the direction of the longitudinal axis 1, a counter-clockwise velocity vector is imposed by ears 16 and 18 of element 6. Subsequent to the flat portion 10, ears 12 and 14 impose a further counter-clockwise velocity vector. It will also be noted that ears 16 and 18 impose a substantially inward directed radial velocity vector on materials moving longitudinally, whereas ears l2 and 14 impose a substantially outward directed radial velocity vector. In a similar manner in FIG. 3, ears 26-28 and 22-24 impose both a clockwise rotating velocity vector and impose generally inward and outward radial vector, respectively.

When a pair of elements 6 and 8 are nested together as in FIGS. 1, 4, l1 and 12, the axially overlapping portions of the elements where the ears mesh defines what can be termed a mixing matrix zone where the longitudinally moving material has counter-rotating velocity vectors induced thereon with simultaneous inward and outward radial vectors. These complex mutually opposed angular and radial vectors result in mutual shearing effects which cause the materials to mix and recombine in a different configuration subsequent to the mixing matrix as the materials flow briefly past the flat central region (10, 20) of the element 6 or 8. This flat central region (10, 20) or non-axially overlapping length of the elements 6,8 has been found to contribute significantly to the successful operation of the present invention. The longitudinal length of the flat regions 10, 20) is preferably long enough to permit relatively complete mixing of the materials subsequent to the mixing matrix, yet is not so long as to materially affect the pressure drop of the apparatus. For any particular application, the flat region length must be considered with respect to pressure drop. In any case, the flat region length is a substantial portion of the gross length of each element, the desired length being further affected by the ear angle (A). The flat region (10,20) length will typically be at least of the same order of length as the mixing matrix zone length.

Although in one aspect the invention is not limited to use with a particular driving source for the materials to be mixed, the invention in another aspect forms a combination of a distribution head and the stationary material mixing apparatus of FIGS. 112. Also, a consideration of the distribution head will permit a further explanation of the apparatus of FIGS. 1-12. The outputs of the distribution heads are, of course, coupled to the input of the mixing apparatus.

FIG. 12 shows a T-junction or manifold for driving two material sources through a single conduit. A driving source, shown as a hand 40, simultaneously drives a pair of pistons 42 and 44 via a U-shaped rod 46. Material A in chamber 48 and material B in chamber 50 are thus driven by the pistons through a T-junction 52 into a conduit 54. Of course, the driving source 40 may be mechanized rather than manual.

A perspective view of conduit 54 in FIG. 14 shows the manner in which materials A and B tend to initially locate in the conduit. In relation to the l or longitudinal axial direction of conduit 54 the material is perfectly mixed. In the plane normal to the Z axis, there are equal amounts of materials A and B (for identical pistons 42, 44 and chambers 48, 50). That is, if a volume of one material is mixed perfectly with a volume of another material, then the probability of finding 3 molecule of one or the other material within the mixed volume is proportional to the initial volume ratios. Viewed another way, all information" has been removed from the system, i.e., one cannot from geometrical considerations alone determine whether we will find one material or another at any arbitrary point. The materials A and B as shown distributed in conduit 54 are not, however, perfectly mixed in the r and 0 directions.

FIG. shows a coaxial distribution head. The driving sources for materials A and B are not shown but may take any suitable form. Material B enters a conduit 60 which passes through a chamber 62 which chamber narrows to a coaxial conduit 64 around conduit 60. Chamber 62 receives material A through an input conduit 66. FIG. 16 shows the distribution of materials A and B in coaxial conduits 60 and 64. It will be apparent that the materials are now perfectly mixed, i.e., contain no information in the I and 0 directions, leaving only the r direction.

In addition to reducing the information of the materials supplied, a coaxial distribution head has a further advantage when used with the stationary material mixing apparatus of FIGS. 1 12. By making the coaxial conduit ends coplanar or by making the center tube protrude with respect to the other tube the distribution head will require little or no cleaning since the materials will come in contact only in the stationary material mixing apparatus. This is of particular significance where materials A and B are reactive materials such as epoxy resins, for example. By fabricating an inexpensive mixing apparatus, the mixing apparatus could be disposable while the distribution head could be used indefinitely. For example, after mixing materials, the apparatus of FIGS. 1 12 would be uncoupled from the distribution head and the distribution head could be simply capped as by an inexpensive rubber or plastic component.

The coaxial distribution head may, of course, have multiple conduits as triaxial, etc.

Referring again to the stationary material mixing apparatus of FIGS. 1 12, it will be appreciated that the invention is useful for mixing all types of materials including liquids, solids, gases, foams, etc. Thenumber of elements 6 and 8 employed can be varied depending on the degree of mixing required and on the type of material being mixed. Because elements 6 and 8 are not permanently fastened to each other or to the chamber 4 walls, the conduit 2 can be a flexible material so that the apparatus can take various curved shapes as may be required in particular applications.

The operation of the present invention can be analogized to the operation of a klystron. In a klystron (see, for example. McGraw-Hill Encyclopedia of Science and Technology, McGraw-Hill, 1971, Vol. 7, pp. 411-413) velocity modulation is imposed on a uniform beam of electrons (having no information," i.e., no variations in the l, r or 0 directions) in a buncher." After flowing along a drift space" the electrons gather into bunches (having information in the 1 direction, but uniform in the r and 9 directions). In the present invention the reverse effect is being accomplished. That is, the input materials are organized (contain information) and the output is desirably a stream of uniform distribution poorly organized no information. In the case of the present invention the mixing matrix is an unbuncher which, like the klystron, requires a subsequent drift space for the results to take effect.

In view of the foregoing modifications to the disclosed embodiments within the spirit of the invention will be apparent to those of ordinary skill in the art. The scope of the invention is therefore to be limited only by the appended claims.

I claim:

1. Stationary material mixing apparatus, comprising a conduit having a length, a longitudinal axis through said length, and a chamber extending longitudinally through said length opening on first and second ends of said conduit and including said longitudinal axis,

a plurality of abutting, self-nested elements fitted within said chamber, adjacent elements being configured as mirror images of one another, each element having lengths along the longitudinal axis where adjacent elements axially overlap defining mixing matrices inducing both counter-rotating angular velocities relative to said longitudinal axis and simultaneous inward and outward radial velocities relative to said longitudinal axis on materials moving through said mixing matrices, each element having a length along the longitudinal axis where said elements do not axially overlap, the axially non-overlapping lengths of said elements along the length of the longitudinal axis defining drift spaces for the recombination of said materials subsequent to movement through the mixing matrices.

2. The combination of claim 1, wherein each of said elements comprises a flat rectangular central portion having first and second sets of ears adjacent opposite sides of said central portion, said sets of ears including first and second ears bent upward and downward relative to the plane of said central portion, said flat central portion lying along said axially non-overlapping length, and said sets of ears lying along said axially overlapping lengths.

3. The combination of claim 2 wherein the included angle defined by said first set of ears is in the range of about 30 to about 4. The combination of claim 3 wherein the included angle defined by said second set of ears is in the range of about 30 to about 120.

5. The combination of claim 4 further comprising coaxial distribution head means coupled to one end of said conduit means.

6. The combination of claim 3 further comprising coaxial distribution head means coupled to one end of said conduit means.

7. The combination of claim 2 wherein the outer periphery of said ears is configured to conform generally to said chamber.

8. The combination of claim 7 further comprising coaxial distribution head means coupled to one end of said conduit means. I

9. The combination of claim 2 further comprising means for coaxially distributing fluid coupled to one end of said conduit means.

10. The combination of claim I further comprising means for coaxially distributing fluid coupled to one end of said conduit means.

Q I m UNITED STATES PATENT" AND TRADEMARK OFFICE 1 n r 1 1 1 1r CILRTII' ICA PE 01* CORRL [ION PATENT NO. 3,923,288

DATED 26 975 INVEN'TOR(S) LEONARD TONY KING It is certified that error appears in the above-identified patent and that said Letters Petent are hereby corrected as shown below: Q

In column 1, line 21, "in" should be -is.

In column 2, lines 16 and I8, "left-hand" should be in quotes.

lines 21 and 23, "right-hand" should be in quotes.

In column 3, lines 3, 5 and 6, "left-hand" and "righthand""should be in quotes.

In column 5, line 25, "perfectly mixed" should be in quotes; Q I line 67, "information" should be in quotes.

In column 6, line 2, "information" should be in quotes; M I Claim 8, line 2, --means for-- should be inserted before "coaxial"; same Q line, "coaxial" should be --coax ially-; same line, "distribution" should be -distributing and ---fluid--,- should be substituted for "head means".

Signed and Scaled this 0 [SEAL] Seventh y of p mber 1976 Alien:

:UTH. C. MA'SON C. MARSHALL DANN "flung Offm mmr'ssiuner nj'larems and Trad k 

1. Stationary material mixing apparatus, comprising a conduit having a length, a longitudinal axis through said length, and a chamber extending longitudinally through said length opening on first and second ends of said conduit and including said longitudinal axis, a plurality of abutting, self-nested elements fitted within said chamber, adjacent elements being configured as mirror images of one another, each element having lengths along the longitudinal axis where adjacent elements axially overlap defining mixing matrices inducing both counter-rotating angular velocities relative to said longitudinal axis and simultaneous inward and outward radial velocities relative to said longitudinal axis on materials moving through said mixing matrices, each element having a length along the longitudinal axis where said elements do not axially overlap, the axially non-overlapping lengths of said elements along the length of the longitudinal axis defining drift spaces for the recombination of said materials subsequent to movement through the mixing matrices.
 2. The combination of claim 1, wherein each of said elements comprises a flat rectangular central portion having first and second sets of ears adjacent opposite sides of said central portion, sAid sets of ears including first and second ears bent upward and downward relative to the plane of said central portion, said flat central portion lying along said axially non-overlapping length, and said sets of ears lying along said axially overlapping lengths.
 3. The combination of claim 2 wherein the included angle defined by said first set of ears is in the range of about 30* to about 120*.
 4. The combination of claim 3 wherein the included angle defined by said second set of ears is in the range of about 30* to about 120*.
 5. The combination of claim 4 further comprising coaxial distribution head means coupled to one end of said conduit means.
 6. The combination of claim 3 further comprising coaxial distribution head means coupled to one end of said conduit means.
 7. The combination of claim 2 wherein the outer periphery of said ears is configured to conform generally to said chamber.
 8. The combination of claim 7 further comprising coaxial distribution head means coupled to one end of said conduit means.
 9. The combination of claim 2 further comprising means for coaxially distributing fluid coupled to one end of said conduit means.
 10. The combination of claim 1 further comprising means for coaxially distributing fluid coupled to one end of said conduit means. 